Different domains of expertise, handled to the same standard. The main ones are described in detail below.
Security
Security monitoring and log correlation, system hardening against recognised benchmarks, audit logging, identity and access management with SSO and MFA, vulnerability scanning, and secure remote access. Experience with cybersecurity standards and certification programmes, covering management-system documentation as well as the technical controls that support it.
Applications
Full-stack web platforms, backend services and APIs, integration with third-party systems, data pipelines and automated reporting.
Designing the implementation and building the infrastructure it runs on, including on-premises hardware where data cannot leave the building.
Databases
Relational and time-series systems in production: high-availability clustering with automated failover, replication, migration onto new architecture without downtime, version upgrades, and query and index tuning.
Network
Routing, segmentation and firewall policy; reverse-proxy and application-delivery layers; site-to-site VPN connectivity to remote sites, including cellular links with automatic failover where no fixed line exists.
Infrastructure
Design and operation of private cloud environments on VMware vSphere and Proxmox VE, hosted or on-premises: sizing, hypervisor and guest tuning, storage layout, and backup and recovery strategies that are tested rather than assumed. Specification of physical server and storage hardware for isolated environments where public cloud is not an option.
Field equipment
Building and industrial automation, field protocols, centralised supervision, and submetering across electricity, gas, water and thermal.